An Internet Telephone Software System for Real-Time Voice Communication

This paper describes the design and implementation of an Internet Telephone Software System which allows real-time full duplex voice communication between two parties through the Internet. The system consists of two main components: Telephone Exchange and Telephone Software. The Telephone Exchange manages a list of active users who are connected to the system, establishes the telephone connection and monitors the quality of services. The Telephone Software is responsible for controlling session and audio management processes. Session management is concerned with the negotiation of communication parameters between two parties before actual communication can take place. Audio management is responsible for audio transmission and the recording and playback operations of audio data. The system has been implemented on Unix-based Sun Sparc workstations using Sun audio cards at the School of Applied Science, Nanyang Technological University. This paper discusses a number of design issues in the development of Internet telephone systems and shows how these are considered in the implementation of the Internet Telephone Software System.